1. Technical Field
This invention relates to electrical junction box container apparatus and associated methods for providing and installing embedded container base junction box/light supports and sign junction boxes. In one aspect, the invention relates to container base apparatus and installation methods for specialized airport edge lighting systems and signs used for the purpose of guiding pilots on an airport runway and during the taxi of aircraft.
2. Background
Conventional edge lighting fixtures forming part of specialized airport edge lighting systems are mounted on containers and associated elements of hardware which also can be viewed as canister set apparatus. The bottom sections of the containers are sometimes called container bases, e.g., edge light container bases. The container bases for these airport edge lights are set along the edge of runways, taxiways, and other aircraft ground traffic areas. The top sections are manufactured in different fixed lengths and diameters. These conventional canisters or container bases and associated elements of hardware, in addition to serving as apparatus for mounting the edge lighting fixtures, also serve as transformer housings and junction boxes to bring electrical power to edge lighting fixtures and to airport signs.
In the installation and support of airport runway edge lighting systems, as well as in the construction or installation and support of taxiway edge lighting systems, and other airport runway lighting systems, the container bases are embedded in the ground, typically alongside of the runway, taxiway, and other pavements. These containers vary in length and diameter. The conventional, existing art containers provide means at their top portion to allow for the runway, taxiway, edge, and other light fixtures to be bolted onto them above the surface, or to allow for the top section of the container to be bolted onto the container bottom section, if it is a two-section container. Each airport paving project may consist of installing hundreds or more edge lighting fixtures and their airport edge light container bases.
Containers used as mounting bases for airport edge lights are generally designated in FAA specification #AC 150/5345-42 as type L-867 Class I. They are designed to withstand light vehicular loads and are subject to direct earth burial with or without concrete encasement. Project design engineers specify whether to use concrete to encase the containers or to bury them directly in the soil. The concrete-encased containers are the most frequently installed, and concrete encasement is considered standard practice.
In the description of conventional containers and their installation, conventional containers can be pre-cast in concrete and then buried in an earthen hole. The conventional containers also can be cast-in-place or can be buried directly without any concrete around the container.
FAA specification #AC 150/5345-42 does not mandate one way or the other, but it is common practice to utilize concrete-encased containers. It generally is specified by the project design engineer to utilize concrete-encased containers, whether pre-cast or cast-in-place. The concrete is placed around the container mainly for stability to withstand overturning and for securely anchoring the container to the earth. Both the pre-cast and the cast-in-place containers can be installed in paved as well as non-paved areas.
Since one of the purposes for the installation of these containers is to use them as electrical junction boxes, it is common practice at the time the containers are first installed to cut a trench approximately four inches wide, using a Vermeer or similar equipment, along the entire length of the installation parallel to the runway or taxiway. The trench is cut in the ground or in the asphalt shoulder before installing the containers and is used for laying conduit, generally plastic type, which is used for bringing electrical power cables to each junction box in the system.
A relatively large hole must be dug in the ground or in the pavement shoulder of an airport runway or taxiway. When the airport edge lighting system is installed for the first time, the bottom sections of the conventional containers are set in the ground in holes considerably larger than the container's bottom sections. The conventional container then can be placed/buried in the earthen hole.
The electrical contractor installs an isolation transformer inside the containers together with electrical wires and wiring devices required for powering airport edge lights and airport signs. Such installation typically is done through an opening at the top of the container. These containers are generally provided with a grounding lug.
Electrical conduit is installed in trenches in the ground and fastened to the containers. Electrical wires are pulled through and into each container. The trenches then are filled around the containers to encase and anchor them in the ground.
Hall et al., U.S. Pat. No. 5,297,013, disclose an outdoor light fixture on an underground anchor stake. Electrical wire for providing power to the light is run down the stake through a stake channel until the wire is below ground.
Knowles, U.S. Pat. No. 5,082,231, discloses a sign support including a post-receiving collar affixed to fins.
Trainor, U.S. Pat. No. 5,029,054, discloses a light base and transformer housing for an airport light comprising a unitary housing made from a noncorrosive material provided with external vertically extending fluted indentations so that the housing will have greater compressive strength and will resist movement in the ground when installed therein and after concrete or bitumen has been poured around the housing.
Carter, U.S. Pat. No. 4,858,877, discloses an outdoor light fixture on an underground nonconductive plastic pipe with an end for receiving electrical conductors or electrical conduit. Stabilizer plates are secured to the pipe in the ground for stabilizing the pipe to prevent the pipe from moving.
Trainor et al., U.S. Pat. No. 4,622,435, disclose an adjustable light base and transformer housing for a runway light to be embedded in an airport runway when the runway pavement is constructed for the first time. In installing the adjustable light base and transformer housing, the cylinder is placed in a previously dug hole on compacted subsoil in the usual fashion (Col. 2, lines 49-51).
Cassey, U.S. Pat. No. 3,805,055, discloses a removable outdoor light having a base member with fins installed in the earth and having electric contacts for making electrical connection with a removable electric post light.
Ewing, U.S. Pat. No. 3,519,726, discloses a transformer vault for underground installation and apertures to permit passage of electrical cables.
There are many costly problems and drawbacks associated with the utilization of conventional containers in the conventional or prior art methods. One problem is the expense involved in setting the containers in the ground in holes larger than the container's bottom sections. Another drawback is the requirement for closing up the hole after the container is placed in the ground and installed. Still another drawback of conventional apparatus and methods involves the requirement for a concrete encasement, used for its mass to provide a structural foundation for load support.
In the installation of concrete-encased canisters by the conventional methods, site layout is performed, equipment is deployed, the site is excavated, the spoils are removed, and a stone sub-base sometimes is placed in the excavated hole. The work requires a backhoe, a truck, and equipment operators and canister installers as well as one or more laborers depending on the size of the job. Materials, such as the stone for the sub-base, also are required. In the case of airport runway work, all construction debris and equipment must be removed from the work site by the end of each work day.
The concrete must be mixed, concrete pouring forms must be built, and then the concrete encasement is poured. This work requires a carpenter, a laborer, and the material, i.e., cement and gravel for the concrete, on-site water, and forms. Again, in the case of airport runway work, all construction debris and equipment must be removed from the site at the end of the work day.
Next, the forms must be stripped, and back-filling around the foundation must be performed. This work requires a backhoe, the operator, a carpenter, a laborer, and materials used to backfill and seed the area.
Conventional methods require the concrete to cure for about seven (7) days. This concrete curing sometimes takes longer depending on the type of concrete used. If testings show the concrete not to comply with a specified strength within the first seven (7) days, then it is required to wait twenty-eight (28) days before any structure can be installed upon the concrete.
In conventional methods of installation for a structure supported by a concrete encasement, some of the major drawbacks of the conventional installation method are apparent. These drawbacks include lengthy installation times and prolonged runway and taxiway closure time in the case of airports. These drawbacks further include increased labor costs, weather dependent operation, and an increased risk, attributable to the many truck trips required, of debris falling on the runway or aircraft traffic areas.
It is therefore an object of the present invention to provide apparatus and method for providing and installing an embedded container junction box with efficiency, simplicity, and precision.
It is a further object of the present invention to provide apparatus and method for providing and installing an embedded container with efficiency, simplicity, and precision together with a lighting fixture installed upon the embedded container apparatus of the present invention.
It is yet another object of the present invention to provide apparatus and method for installing a container base in the ground without the need for digging holes larger than the container's bottom sections.
Another object of the present invention is to provide apparatus and method for installing a container base apparatus which provides good stability and strength in the ground capable of withstanding typical airport runway edge lighting and sign loads.
Another object of the present invention is to provide apparatus and method for installing with efficiency, simplicity, precision, and stability a container base apparatus in the ground while eliminating the need for concrete encasements around the container's bottom sections and providing good stability and strength capable of withstanding typical airport runway edge lighting and sign loads.
Still another object of the present invention is to provide apparatus and method for installing a container base apparatus which eliminate the need for digging apparatus and soil removal for setting the containers in the ground in holes larger than the container's bottom sections.
It is a still further object of the present invention to provide apparatus and method for installing with efficiency, simplicity, precision, and stability a container base apparatus and method which eliminate the problems associated with and experienced in conventional practices.
These and other objects of the present invention will be described in the detailed description of the invention which follows. These and other objects of the present invention will become apparent to those skilled in the art from a careful review of the detailed description and from reference to the figures of the drawings.